Re: Forth for Mac OS X Leopard (Intel) - what are the options?

Albert van der Horst <albert@[EMAIL PROTECTED]
> wrote:
>
> Also default linking will select a start address for you.
> For some reason a normal start address in linux32 is around
> HEX 0804,0000 and on linux64 it is HEX 0000,0060,0000,000.
> You don't want to think about where to find documentation
> to select a reasonable address here. It certainly takes more
> time to then porting to linux64 has take me now ;-).

Er...documentation on selecting a "reasonable address" may be hard
to find, but getting the default start address is utterly trivial.

On a GNU system, do 'objdump -h foo' on any binary foo generated
by the usual linking process, find the .text section, and subtract
the file offset from the address.  Looks like you should be able
to do the same thing on an Apple system with 'otool -l foo' with
the segment_command for __TEXT.

If you want to do it the hard way (again, on GNU systems) you can
run 'ld --verbose' (no other arguments).  It will spit out the
default linker script, and somewhere near the top will be the
default start address.  It should be just about the first thing
inside the SECTIONS block, and there is probably an occurrence of
SIZEOF_HEADERS nearby.  On my system:

using internal linker script:
==================================================
....
SECTIONS
{
  /* Read-only sections, merged into text segment: */
  PROVIDE (__executable_start = 0x08048000); . = 0x08048000 +
SIZEOF_HEADERS;
....

> I have some experience with linker scripts in GNU (for embedded
> work) and it is an issue to avoid if at all possible.

Linker scripts aren't bad.  Not well documented, but in my
experience they aren't at all hard to use once you understand
what's going on.

--Josh